a) Field of the Invention
The present invention relates to a rotating electrical machine capable of performing power generation and electric power generation, and a hybrid drive unit provided with the same.
b) Description of the Related Art
For a hybrid drive unit having an engine and an electric motor as power generation sources, there is proposed, for example, the structure shown in FIG. 8. In the structural example shown in FIG. 8, the power of an engine 136 is divided in two by a power distribution mechanism 137 which is comprised of a planetary gear mechanism. One half of the distributed power of the engine 136 is transmitted to a wheel 138, and the other half of the distributed power of the engine 136 is converted into electrical power generated by an electrical generator 114. The electrical power generated by the electrical generator 114 undergoes electrical power conversion by the inverters 140, 141 (from AC to DC by an inverter 140, and from DC to AC by an inverter 141) and supplied to a motor 112. The motor 112 drives to rotate the wheel 138 by converting the supplied electrical power into the power of a rotor (not shown). Thus, the structure shown in FIG. 8 is provided as a power transmission path between the engine 136 and the wheel 138 with a transmission path (transmission path based on a mechanical path) which transmits the mechanical power from the engine 136 to the wheel 138 and a transmission path (transmission path based on an electric path) running via the electric generator 114, the inverters 140, 141, and the motor 112.
Also, structures of rotating electrical machines are disclosed in, for example, Japanese Patent Laid-Open Publication No. 2001-339976 (Patent publication 1), Japanese Patent Laid-Open Publication No. 2001-258159 (Patent publication 2) Japanese Patent Laid-Open Publication No. 2002-95288 (Patent publication 3), and Japanese Patent Laid-Open Publication No. Hei 11-168852 (Patent publication 4). The rotating electrical machines according to Patent publication 1 and Patent publication 3 are configured of two induction machines each having a stator and a rotor. The rotors of the two induction machines are mutually coupled, and the rotor windings of the two induction machines are mutually connected.
The rotating electrical machine according to Patent publication 2 is comprised of an induction machine having a stator and a rotor and a synchronous machine having a stator and a rotor. Also, the rotor of the induction machine is coupled to the rotor of the synchronous machine.
The rotating electrical machine according to Patent publication 4 comprises a first stator which has a first armature coil for mainly conducting conversion of energy with the outside, a first rotor which is disposed facing the first stator with a gap between them, a second stator which has a second armature coil and is disposed to face the first rotor with another gap between them, a flywheel which is supported by the rotation shaft of the first rotor so to be independently rotatable, and a second rotor which is coupled to the flywheel at a position facing the first rotor with another gap between them. Conductors are respectively disposed on a surface of the first rotor facing the second stator and another surface facing the second rotor, and they are connected. A conductor is also disposed on a surface of the second rotor facing the first rotor. According to Patent publication 4, the induction machine is configured of the first rotor and the second stator which are disposed facing each other. Another induction machine is also configured of the first rotor and the second rotor which are disposed facing each other.
According to the above-described structural example shown in FIG. 8, the power is transmitted through the electrical path via the inverters 140, 141, but the electrical power conversion by the inverters 140, 141 causes loss. Therefore, the loss caused when the power is transmitted through the electric path increases, resulting in a problem that power transmission efficiency is lowered.